Prior art high modulus polyurethane resins typically have high viscosities and are waxy solids at room temperature. Due to these properties it is inconvenient to use these high modulus resins for non-hot melt adhesives.
Polyurethane and acrylic copolymers compositions are know in the art. For example, Kanegafuchi, JP 07011223, discloses a polyurethane and acrylic copolymer for preparing coating primer. Kanegafuchi discloses silane-acrylic copolymers prepared by co-polymerizing methacryloxysilanes.
Silane-modified acrylic polymers are also known in the art. For example, Essex, U.S. Pat. No. 4,491,650, discloses silane-modified acrylic polymers for use in primers. These polymers are unsuitable for use as adhesives because they are brittle.
Published U.S. Patent Application No. 2006/0173121 discloses a curable composition containing silylated polyoxyalkylene polymer, copolymers of methacryloxysilane and acrylic acid alkyl ester monomers and an ionic surfactant. However, the glass transition temperatures for these copolymers must be lower than 0° C. for flexibility.
Most one-part high modulus silane-terminated polymer resins or resin blends are either waxy or highly viscous at room temperature due to the semi-crystallinity of the polymers used or strong internal interactions.
There remains a need in the industry for curable silane-terminated resins for use in non-hot-melt adhesives which are flowable at room temperature and cure into high modulus products. The present invention, as described more fully herein, provides such compositions.